refactor(mbedtls): rename default mbedtls confs

Change the name of these confs to be version agnostic,
we will later use these configs to enforce the mbedtls
minimum version

Change-Id: I1f665c2471877ecc833270c511749ff845046f10
Signed-off-by: Ryan Everett <ryan.everett@arm.com>
(cherry picked from commit 640ba6343bc86068178d7ac5cf3d3275f30d6ffb)
diff --git a/drivers/auth/mbedtls/mbedtls_common.mk b/drivers/auth/mbedtls/mbedtls_common.mk
index 656acab..fc22211 100644
--- a/drivers/auth/mbedtls/mbedtls_common.mk
+++ b/drivers/auth/mbedtls/mbedtls_common.mk
@@ -24,7 +24,7 @@
 endif
 
 # Specify mbed TLS configuration file
-	MBEDTLS_CONFIG_FILE	?=	"<drivers/auth/mbedtls/mbedtls_config-3.h>"
+	MBEDTLS_CONFIG_FILE	?=	"<drivers/auth/mbedtls/default_mbedtls_config.h>"
 
 $(eval $(call add_define,MBEDTLS_CONFIG_FILE))